SN74ALS869NT

Counter Dividers Overview

The SN74ALS869NT is a synchronous 8-bit up/down counter from the Texas Instruments ALS logic family, housed in a standard plastic 24-pin DIP (NT) package. It operates within a supply voltage range of 4.5 V to 5.5 V and supports clock frequencies up to 35 MHz. The device features internal carry look-ahead circuitry for high-speed cascading and includes two count-enable inputs (ENP, ENT) and a ripple-carry output (RCO). It performs fully programmable parallel loading and utilizes a buffered clock input that triggers flip-flops on the rising edge. The SN74ALS869 incorporates synchronous clear functionality, distinguishing it from asynchronous variants.

Counter Dividers Feature Summary

• Synchronous operation with simultaneous flip-flop triggering eliminates output counting spikes associated with asynchronous counters.
• Internal carry look-ahead circuitry enables efficient n-bit cascading without additional external gating.
• Fully programmable architecture allows presetting to any value between 0 and 255 via synchronous parallel loading.
• Directional control is managed through independent select inputs, supporting both up and down counting modes.

Counter Dividers Applications

• High-speed binary counting applications requiring synchronized state changes
• Cascaded multi-stage digital systems utilizing internal carry look-ahead
• Programmable timing circuits requiring precise preset values
• Digital systems needing synchronous clear and load capabilities

Counter Dividers Procurement Notes

Verify the specific NT suffix indicates the standard plastic dual-in-line package configuration. Confirm the component matches the SN74ALS869 functional specification rather than the SN74ALS867A variant, which differs by having asynchronous clear. Ensure the operating temperature range aligns with commercial requirements of 0°C to 70°C. Cross-reference the datasheet revision date to confirm electrical characteristics remain consistent with current production data.

Counter Dividers Selection Notes

Select this component when synchronous counting is required to prevent race conditions inherent in ripple counters. The ALS series offers a balance of speed and power consumption suitable for general-purpose digital logic. Consider the SN74ALS867A if an asynchronous clear signal is preferred over synchronous clearing. Evaluate the 35 MHz maximum clock frequency against system timing requirements to ensure adequate setup and hold margins are met during operation.

Counter Dividers Part Context

This device belongs to the Texas Instruments SN74ALS logic family, designed for advanced low-power Schottky applications. It shares the same logical structure as the SN74AS869 but utilizes different semiconductor technology resulting in distinct switching speeds and drive currents. The NT package designation identifies it as a standard plastic DIP, contrasting with ceramic or surface-mount options available within the broader SN74ALS869 product line.

Counter Dividers Replacement Considerations

SN74ALS867ADW serves as a functional alternative if asynchronous clear is acceptable instead of synchronous clear. SN74AS869DW provides higher speed performance but requires verification of pinout and electrical compatibility. SN74ALS869DW is the identical functional equivalent packaged in SOIC format.